If you've been diagnosed with a vitamin D deficiency, the treatment itself is usually simple — supplements, dietary changes, and sensible sun exposure. How quickly you feel better depends on how low your levels were to start with: often just a few days for a severe deficiency, or one to two weeks if you're mainly topping up.
Vitamin D deficiency is common in the UK, and treatment is generally straightforward once it's confirmed with a blood test. In this article, we'll cover what treatment actually involves, what to expect from your doctor, and realistically how long it takes before you notice a difference.
How is a vitamin D deficiency diagnosed and treated?
If you're experiencing symptoms of low vitamin D, the first step is a blood test, either via your GP or an at-home Vitamin D test, to confirm whether you actually have a deficiency rather than guessing from symptoms alone. For the full list of deficiency symptoms and who's most at risk, see our guide to vitamin D deficiency: signs, symptoms and what to do.
In all but the most extreme cases, treatment is simple: increase your vitamin D intake through supplements, diet, and sun exposure. If you have a confirmed, notable deficiency, a doctor may recommend a higher-dose supplement or cod liver oil for a set period, alongside dietary changes to include vitamin D-rich foods such as oily fish, mushrooms, egg yolks, red meat, and fortified products.
Sun exposure also matters, particularly since dietary sources of vitamin D are fairly limited. Even in winter, getting outside during any breaks in cloud cover can help, though a supplement is the more reliable option during the darker months.
How long does it take to feel better?
This varies depending on how low your levels were to begin with:
- Severe deficiency: some people notice an improvement within just a few days of starting treatment.
- Mild deficiency or a general top-up: it may take one to two weeks before you start to feel healthier and more energised.
- Full correction of your blood levels: this takes longer than symptom improvement, and is usually assessed with a follow-up blood test around 3 months after starting treatment, rather than judged by how you feel.
It's worth noting that feeling better and your blood levels actually normalising aren't quite the same thing — you may feel improved before your levels are technically back in a healthy range, which is why a follow-up test matters if your deficiency was significant.
What if you don't notice any improvement?
If you've been taking a supplement as recommended and don't notice any change after a few weeks, it's worth going back to your doctor. This can happen if the dose wasn't sufficient for how low your levels were, if there's an absorption issue affecting how well you take up vitamin D, or if your symptoms were being caused by something else entirely alongside the deficiency.
FAQ
Can you feel better within a day of taking vitamin D?
It's unlikely to be that fast for most people, though those with a severe deficiency sometimes notice a difference within a few days. For most people topping up milder low levels, one to two weeks is more typical.
Do I need a follow-up blood test after treatment?
Yes, particularly if you had a confirmed, significant deficiency. Feeling better isn't a reliable substitute for confirming your levels have actually normalised.
Can children recover from vitamin D deficiency the same way?
Children can also be treated with supplements and dietary changes, but should be assessed and monitored by a doctor rather than self-treated, given the risk of more serious effects like rickets and delayed development if left unaddressed.
If you're not sure whether your symptoms are down to vitamin D or something else, our at-home Vitamin D test can confirm your levels without waiting for a GP appointment.
